This application claims the priority of International Application No. PCT/DE2008/000841, filed May 17, 2008, and German Patent Document No. 10 2007 027 335.7, filed Jun. 14, 2007, the disclosures of which are expressly incorporated by reference herein.
The invention relates to an anti-wear coating, in particular an anti-erosion coating, preferably for gas turbine components. The invention also relates to a component having such an anti-wear coating.
Components such as gas turbine components which are exposed to stresses in flow technology are subject to wear due to oxidation, corrosion and erosion. Erosion is a wear process induced by solid particles entrained in the gas flow. To prolong the lifetime of components used in flow technology, anti-wear coatings that protect the components from wear, in particular from erosion, corrosion and oxidation, are required.
European Patent Document No. EP0674020B1 describes a multilayer erosion-resistant coating for the surfaces of substrates. The erosion-resistant coating disclosed there is an anti-wear coating comprising several multilayer systems applied in a repeating order to the substrate to be coated. In EP0674020B1 the multilayer systems applied in a repeating order are thus formed from two different layers, namely first a layer of a metallic material and secondly a layer of titanium diboride. With the anti-erosion coating according to EP0674020B1, the multilayer systems applied in a repeating order are formed from only two layers, so with the anti-erosion coating disclosed there, alternating layers of metallic material and layers of titanium diboride are provided.
European Patent Document No. EP0366289A1 discloses another erosion-resistant and corrosion-resistant coating for a substrate. According to EP0366289A1, the anti-wear coating is also formed from several multilayer systems applied in a repeating order to the substrate to be coated, each multilayer system in turn comprising two different layers, namely a metallic layer, e.g., titanium, and a ceramic layer, e.g., titanium nitride.
Another erosion-resistant anti-wear coating is known from European Patent Document No. EP0562108B1. The anti-wear coating disclosed there is in turn formed from several multilayer systems applied in a repeating order to a substrate to be coated. FIG. 4 of EP0562108B1 discloses an anti-wear coating formed from several multilayer systems applied in a repeating order, each multilayer system comprising four layers, namely a ductile layer of tungsten or a tungsten alloy and three hard layers, such that the three hard layers differ with regard to an additional element content.
Against this background, the present invention is based on the problem of creating a novel anti-wear coating and a component comprising such an anti-wear coating.
According to the invention, all the layers of the/each multilayer system are based on chromium, with a diffusion barrier layer being applied between the surface to be protected and the multilayer system(s).
The inventive anti-wear coating ensures a very good erosion resistance and oxidation resistance. The inventive anti-wear coating has an extremely low influence on the vibration resistance of the coated component. Due to the fact that a diffusion barrier layer is integrated between the component surface and the multilayer system(s), the inventive anti-wear coating has a high thermodynamic stability. The inventive anti-wear coating may be used over a longer period of time at very high temperatures.
The diffusion barrier layer preferably has a mono-nanostructured design and is embodied as a CrN layer in particular.
Preferred further embodiments of the invention are derived from the following description. Exemplary embodiments of the invention are explained in greater detail on the basis of the drawings, although the invention is not limited thereto.